This is very helpful for connecting random ethernet ports
to e.g. DSA switches that typically reside on fixed links.
The phy-mode is still there as the fixes link in this case
is still an RGMII link.
Tested on the Cortina Gemini driver with the Vitesse DSA
router chip on a fixed 1Gbit link.
Suggested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>